iety2004 wrote:I thought it was to stop the body from stretching and twisting when cornering hard and stiffen it up a bit?

It is & it does on `strut type` suspension, where the body is the top suspension mount. On Chevettes/Kadetts, you have a double wishbone setup, it doesn`t use the inner wing tops as a mounting point except for the shock absorber.
As shoveitpusher says, all the suspension stresses go into the engine cross member. if the damper top moves it's not a big deal.

With a coilover setup, the strut tops flexing can allow the wheel camber angle to change appreciably when cornering, thus the fitting of a strut brace is a very good idea. On a car like the chevette where the wheels are firmly located by the double wishbones the wheel camber tends to remain fixed regardless of what the strut tops are doing. As already mentioned, the engine crossmember acts as a lower strut brace here.

Right. To strengthen the crossmember is easy. There is a large space in the middle of it, so what you need to do is fill this with solid metal as the present design allows some flexing. I suggest sourcing a 2"x2" solid length of box section, cut it to length and weld it in whole to your crossmember. Then plate below this to make it completely solid. May I suggest fitting 900lb front springs at the same time.

Doive wrote:I suggest sourcing a 2"x2" solid length of box section, cut it to length and weld it in whole to your crossmember. Then plate below this to make it completely solid. May I suggest fitting 900lb front springs at the same time.

didn't realise you were into tank design, challenger one of yours?

oh and 900lbs springs are smooth tarmac spec for a rally car, racers probably go somewhere near 1200, so to lug you cross member around would need at least 1500lbs springs.

compress them with your corner shop spring compressors

scary or what

i have heard of stock cars with cement boots (as in trunk) but never volcanic granite. does it work?

Nah!, put the spring across a door frame with a bottle jack, between the frame uprights, stand on the spring whilst pumping the jack. When it`s compressed enough, tie it up with a bit of washing line, fit spring & cut the line.....easy peasy.